Epicalida castration - epicalida castration

… [Yoichi Shoda]
[Parasitic castration]
Parasitism causes changes in the host's gonads and secondary sexual characteristics, but the degree of change varies, and in many cases the term castration is inappropriate in the true sense of the word. The best known are sacculina castration, which occurs when parasitism occurs in the abdomen of crabs and hermit crabs (Crustacea: Decapoda) caused by parasitism of sea cucumbers and sea cucumbers (Crustacea: Cirripedia), and epicalida castration, which occurs when parasitism occurs in the gills and abdomen of shrimp and crabs (Crustacea: Decapoda) caused by shrimp and crab parasitism (Crustacea: Isopoda). In the former case, the parasitized male undergoes feminization of external appearance and secondary sexual characteristics, including the degeneration of the testes, the miniaturization of the claws, the reduction of the copulatory organs, the development of the oviductal limbs, and the widening of the abdomen.

*Some of the terminology that refers to "epicalida castration" is listed below.

Source | Heibonsha World Encyclopedia 2nd Edition | Information

…【正田 陽一】
［寄生去勢parasitic castration］
　寄生によって宿主の生殖腺や二次性徴に変化を生じることであるが，その変化の程度はいろいろで，真の意味での去勢の語がむしろ不適当な場合も多い。最もよく知られているのはフクロムシやナガフクロムシ類(甲殻綱蔓脚（まんきやく）類)がカニやヤドカリ類(甲殻綱十脚類)の腹部に寄生して起こるサッキュリナ去勢と，エビヤドリムシやカニヤドリムシ類(甲殻綱等脚類)がエビやカニ類(甲殻綱十脚類)のえらや腹部に寄生して起こるエピカリダ去勢である。前者では寄生を受けた雄は精巣の退化に加えて，はさみの小型化，交尾器の縮小と抱卵肢の発達，腹部の広幅化など外形と二次性徴の雌化が起こる。…

※「エピカリダ去勢」について言及している用語解説の一部を掲載しています。

出典｜株式会社平凡社世界大百科事典 第２版について | 情報